1. Field of the Invention
The embodiments of the present invention relate generally to a filter housing.
2. Background of the Invention
Cleanrooms are utilized in many industries for contamination control and to improve product yields. A plurality of filters, typically mounted in the ceiling of the cleanroom, are configured to remove particulate from air entering the cleanroom at a predetermined efficiency selected based upon the cleanliness requirements of the activities performed in the cleanroom. As particulates load the filtration media disposed in the filter, the airflow through the filter decreases as the pressure drop across the filter increases. Once the filter reaches a critical pressure drop, the filter is typically replaced.
On other applications, replacement of filters is scheduled based on time or processes performed within the cleanroom. For example, in many pharmaceutical and biotech cleanrooms, periodic replacement of filters is required to meet regulatory or owner specifications. To facilitate efficient replacement of the filter, a housing is typically mounted in the cleanroom ceiling in which the filter may be readily removed and replaced.
During the installation of such housings, a hole is frequently drilled through the housing to facilitate mounting or to provide an attachment point for a trim ring commonly used to cover the interface between the ceiling and housing. Fasteners, disposed through the hole, are typically caulked from the cleanroom side to prevent unfiltered air from reaching the downstream side of the filter.
However, seal provided around the fastener is a potential leak path, which may leak due to improper application of the sealing material (e.g., caulk), or by damaging the sealing material during screen or filter installation or replacement. Particularly, if the holes through the housing are in communication with the upstream side of the filters which is at a higher pressure than the cleanroom, unfiltered air may be driven through the hole and into the cleanroom. Thus, it would be desirable for a housing to accommodate mounting holes that are isolated from the pressurized regions of the filter housing that contain unfiltered air.
Therefore, there is a need for an improved filter housing.
A filter housing for retaining a roomside replaceable filter is provided. In one embodiment, the filter housing includes one or more sidewalls defining an interior volume. Each sidewall includes a first section and an adjacent second section sealingly coupled thereto. A sealing member is coupled to the second section and extends into the interior volume. The sealing member is adapted to provide a gas-tight seal with a replaceable filter. A hole is disposed through at least one of the first or second sections. The first section is sealed to the second section around a perimeter of the hole to prevent unfiltered air from entering a cleanroom through the hole.
In another embodiment, a filter housing includes a first sidewall section coupled between a sealing member and a second sidewall section. The sealing member is adapted to provide a gas-tight seal with a replaceable filter element. A barrier ring circumscribes a pass through area formed in at least one of the first sidewall section or second sidewall section. The barrier ring fluidly isolates the pass through area from an interstitial space defined between the first sidewall section and the second sidewall section.
In another embodiment, a filter housing includes a plurality of sidewalls, each sidewall formed of a singular sheet of material and having an outer section coupled to an inner section. A sealing member is coupled to the inner section and adapted to provide a gas-tight seal with a replaceable filter element. A hole formed in the outer sidewall is circumscribed by a fluid seal disposed between the outer section and the inner section.